The invention relates to the field of false partitions, in particular false ceilings and false walls. The invention concerns more particularly an acoustically absorbent assembly for producing false partitions.
The assembly is intended in particular, but not exclusively, to be placed inside premises, such as an apartment, a concert hall, etc, in which it is necessary, apart from concealing unaesthetic equipment such as electric cables, pipework, etc, to control the acoustic behaviour.
It is also intended to be used with luminous means to form luminous false partitions.
Conventionally, false partitions are produced from frames able to be fixed to a wall or ceiling of a room and flexible layers tensioned on these frames. Despite the increasing use thereof in various environments, the false partitions of the prior art produced with tensioned flexible layers have a major drawback, which is having poor acoustic properties. The tensioned layers in fact reflect sound waves, then generating a significant phenomenon of reverberation (or echo) of the sound waves.
In order to overcome this drawback, providing flexible layers provided with microperforations is known from the prior art, in order to increase the absorption of the sound and therefore to attenuate the reflection of sound waves. The microperforated layers do however have the drawback of not being impervious to air, dust and moisture. Moreover, the presence of microperforations allows the passage of air giving rise to dirt.
In order to attempt to overcome these drawbacks of microperforated layers, a flexible layer composed of a first solid fabric and a second perforated fabric was proposed in the application EP 2 078 796, said fabrics being superimposed and assembled at the periphery on an attachment means able to cooperate with rails. The second fabric (the microperforated fabric) is disposed with respect to the first fabric (the solid fabric) so as to be placed on the side visible from the room interior.
Thus, through the presence of a solid fabric, the problems of impermeability are solved. Nevertheless, the presence of the solid fabric has an influence on the global acoustic performances of the tensioned layer. A drop in coefficient of absorption of the tensioned layer has in fact been observed, in particular for sound frequencies above 300 Hz, reaching unsatisfactory values (below 0.35).
There is also known, from the application EP 2 472 018, an acoustically absorbent assembly intended to form, inside an enclosure, at least one partition element, the assembly comprising at least two supports provided with microperforations and a support not comprising microperforations, the support not comprising microperforations being placed on the side that is visible from the inside of the room. Although the acoustic assembly described has satisfactory efficacy, a drop in acoustic performances of the assembly is observed for sound frequencies above 300 Hz, reaching a coefficient of absorption below 0.35 for frequencies above 300 Hz.